The TK fast track is located on the left side of the booths allocated Turkish citizens. See the blue arrow for the exact location of that service.




Also for the meet&greet service, the website istanbulsairport.com looks like a tourist scam as there are no companies operating under the name "MGA" at Istanbul Airport. They seem like a tour agency that takes the money and pay the €99 to iGA and then keep the rest. For their transfer service I have no idea but if they are not an approved transfer company, it's likely that you would spend time finding them either at the public transportation level at the pick-up area or at the carpark. Also, their website in Turkish have grammatical errors in phrases which is totally unprofessional.

The service of iGA would only save you 2-3 minutes in total as you would be transported by a buggy within parts of the terminal and no other service would be provided other than the dedicated fast-track lane and an agent walking with you. IMO, it's not worth it at all, but if you are between meet-and-greet services, I would consider the official one provided by iGA.

For the taxis, there might be a small wait depending on what time you arrive, although there are always luxury taxis ( black taxis ) available at the taxi rack without any wait which would take you wherever you need for double the price of a regular taxi. Most transfer companies at Istanbul are tourist scams, thus I would definitely suggest going to the taxi rack and ride a yellow taxi to your final destination.